Development Of Magnetron Sputtering Thin Film Pressure Sensor

Due to the high-precision, low-creep, strong anti-interference capability and other advantages, sputtering thin film pressure sensors have been widely used in industrial applications. The paper focuses on the development of magnetron sputtering thin film pressure sensor. The main target and tasks are decided based on costs, existing equipments and application requirements. This paper includes developing sensitive element, designing signal processing circuit and designing mechanical structure and then test on the pressure sensor is done. The main contents of this paper are as follows:1. Based on the principle of strain resistors, the working principle of the sensor and the stress distribution of core sensitive element have been studied and then resistors on the sensitive element are determined. The patterns of resistor film and mask, which is used in the sputtering process, are designed according to the characteristics of the sensor and requirements of sputtering technology. By the coating method of magnetron sputtering, mask method and photolithography after sputtering method are carried out to compare manufacture accuracy. Micro electrochemical machining is chose to trim resistor on the basis of the conditions of the resistor membrane after corrosion process.2. In the process of designing signal processing circuit, the sensor's various errors, such as the initial unbalance error, zero shift error and sensitivity temperature error, are compensated. The sensor's output signal is amplified by the use of chip typed INA125 UA.3. Mechanical structure of the sensor is designed, according to the sensor's characteristic and test convenience, including base, connector, sleeve and cover.4. After the design of the sensor being developed, a testing apparatus is established to calibrate the sensor, whose result shows the sensor meets the proposed design requirement.